Where does he learn these things?

The other day Eric's mom was trying to take a photo of Oliver and asked him to turn around. He got a huge grin on his face and just started to spin around and around in circles. This was quite amazing to me since neither Eric nor I had ever taught him to do that or can remember anyone else teaching him. The only explanation is that he picked it up in one of his classes, from a book, or from his friends. He also throws his hands up in the air when ever he hears the phrase "all done". Once again, I'm not sure where he learned this....